Specifications
PS Engineering 
PMA8000B Audio Selector Panel and Intercom System 
Installation and Operator’s Manual 
200-890-0100  Page 3-4  Rev. 13, Dec. 2009 
ternal) are in working order. TST does not activate MM autopilot sense output. Releasing the button r e-
turns to the last sensitivity.  
Pressing the marker mode select (“T/M”) for one second will also cause the marker audio to mute for that 
beacon. The next beacon received will re-activate the audio. 
3.7  Intercom Operation 
3.7.1  IntelliVox® VOX-Squelch 
No  adjustment  of  the  IntelliVox®  squelch  control  is  necessary.  There  is  no  field  adjustment.  Through 
three individual signal processors, the ambient noise appearing in all six microphones is constantly being 
sampled.  Non-voice  signals are  blocked.  When  someone  speaks,  only  their  microphone  circuit  opens, 
placing their voice on the intercom. 
The  system is  designed to  block  continuous tones; therefore people humming or  whistling in monotone 
may be blocked after a few moments. 
For consistent performance, any headset microphone  must be placed within ¼-inch of your lips, prefera-
bly against them. (ref: RTCA/DO-214, 1.3.1.1 (a)). 
NOTE 
It is also a good idea to keep the microphone out of a direct wind path. Moving your head through a vent 
air stream may cause the IntelliVox® to open momentarily. This is normal. 
The IntelliVox® is designed to work with normal aircraft cabin noise levels (70 dB and above). It loves 
airplane noise! Therefore, it may not recognize speech and clip syllables in a quiet cabin, such as in the 
hangar, or without the engine running. This is normal.  
For  optimum microphone performance, PS Engineering recommends installation of a Microphone Muff 
Kit from Oregon Aero (1-800-888-6910). This will not only optimize VOX performance, but will improve 
the overall clarity of all your communications. 
Table 3-1 Mic Muff ™ Part Numbers 
Manufacturer 
Model 
Mic Muff™ Part Number 
Bose 
Dynamic 
Electret 
M87 Dynamic 
90010 
90015 
90020 
David Clark 
H10-30 
H10-20, H10-40 
H10-13.4 
90010 
90015 
90015 
Lightspeed 
All 
90015 
Peltor 
7003 
7004 
90010 
90015 
Pilot 
11-20 & 11-90 
90015 
Sennheiser 
90015 
Telex 
Airman 750, Echelon 
AIR3000 
90015 
90010 
3.7.2  Intercom Volume Control (7) 
The  inner  volume control  knob  adjusts  the  loudness  of  the intercom for the pilot and copilot. It  has no 
effect on selected radio levels, music input levels or passengers' volume level. 
The outer volume control knob controls intercom volume or the passengers. It has no effect on radio or 
music levels. 
Adjust the radios and  intercom volume for a comfortable listening level. Most general aviation headsets 
today have built-in volume controls; therefore, volume also can be further adjusted at the individual head-
set. 










